Tryptophane in Proteolysis. 
BY 
S. H. VINES, M.A., D.Sc., F.R.S., P.L.S. 
Sherardian Professor of Botany in the University of Oxford. 
T HE last number of the ‘Annals of Botany ’ contains 
a paper (1) in which I adduce evidence to prove that 
the proteolytic enzyme of Nepenthes , as well as those of the 
Pine-Apple (bromelin) and of the Papaw (papain), are essen- 
tially ‘ tryptic ’ in their mode of action. The evidence consists 
in the demonstration, by means of the chlorine-water test, 
of the presence of a substance, known as tryptophane, among 
the products of digestion. It is, I believe, generally accepted 
that the formation of this substance is an indication of the 
disruption of the proteid molecule into non-proteid substances 
which is held to be characteristic of ‘ tryptic ’ digestion. The cor- 
rectness of this view of the physiological significance of trypto- 
phane has been confirmed by the recent researches of Hopkins 
and Cole (2), who find that its formula is C n H 12 N 2 0 2 , and 
that it abundantly yields skatol and indol on heating. 
I propose, in the present paper, to give a more complete 
account of my observations on bromelin and papain, and to 
describe further experiments which I have made with the 
enzymes of the Fig ( Ficus Carica , L.), of the Coco-Nut 
( Cocos nucifera , L), of germinating seeds of the Bean ( Vicia 
Faba , L.) and of the Barley ( Hordeum vulgar e, L.), of Yeast 
( Saccharomyces Cerevisiae , Meyen), and of the Bacteria of 
putrefaction, as also with animal pepsin. I will so far 
anticipate as to say at once that in all these cases, under 
appropriate conditions, I have succeeded in finding trypto- 
[Annals of Botany, Vol. XVI. No. LXI. March, 1902 ] 
